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Author: Subject: Diethyl Ether - Solution did not Turn Black - SEP Funnel no Separation?
LuckyWinner
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[*] posted on 11-8-2020 at 01:21
Diethyl Ether - Solution did not Turn Black - SEP Funnel no Separation?


did the ususal diethyl ether
Et-O-Et from dehydration of EtOH
as seen here
http://www.sciencemadness.org/talk/viewthread.php?tid=9747


drip freezer cooled ethanol 95% into 95% sulfuric acid
under heavy mag stirring. (20min)

setup for fractional distillation.
all parts are insulated in aluminium foil 5x times.

raise aluminium heating block temperature to 150C (max temperature, otherwise ethylene gas is favored)
*this maybe does not translate to 150C flask temperature?

distillate comes over VERY SLOWLY at ~39C, added ethanol from dripping funnel in a
higher rate then product is generated, since distillation took over 5 hours already...
temp rose to ~65C and stayed till no more distillate came over.

NOTE: main reaction flask did NOT turn color to black!

washed 'ether' 2x with sodium bicarbonate
1x nacl

only a tiny layer separated on the top.
the rest is unreacted ethanol? (seems to be the same amount that was added
to the dropping funnel. (reeks of ether)


-solution, my reaction temperature did not reach 140C and
ethanol directly evaporated over once it dripped onto the hot sulfuric acid.
magnetic stirring was not high enough?

only a few drops of ~39C distillate came over , then temp rose to 65C for the rest of the
reaction.

flask contents are still clear (sul acid, ethanol)
I guess I can reuse this?


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draculic acid69
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[*] posted on 11-8-2020 at 05:48


I think your supposed to drip ethanol into hot acid not mix them and then heat it
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macckone
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[*] posted on 11-8-2020 at 07:05


It sounds like your hot plate wasn't getting the reaction mixture hot enough, then you flooded it with ethanol.
If too much water or ethanol is added then sulfuric acid loses its effectiveness as the catalyst.
In commercial operations the sulfuric acid is cycled to dry it.
Every mole of ether that is produced makes a mole of water.
edit:
You were using 95% ethanol, that contains water, you definitely flooded your reaction.

[Edited on 11-8-2020 by macckone]
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LuckyWinner
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[*] posted on 11-8-2020 at 07:59


Quote: Originally posted by macckone  
It sounds like your hot plate wasn't getting the reaction mixture hot enough, then you flooded it with ethanol.
If too much water or ethanol is added then sulfuric acid loses its effectiveness as the catalyst.
In commercial operations the sulfuric acid is cycled to dry it.
Every mole of ether that is produced makes a mole of water.
edit:
You were using 95% ethanol, that contains water, you definitely flooded your reaction.

[Edited on 11-8-2020 by macckone]


correct, that must be the case.

that means my distillate is ethanol/water mostly?

this can be fractionally distilled to reuse the ethanol.

and the solution that is left from my reaction flask is sulfuric acid/ water mixture.
this can be boiled to re concentrate the sulfuric acid to 95% ?
then reuse
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[*] posted on 11-8-2020 at 19:38


Quote: Originally posted by LuckyWinner  
Quote: Originally posted by macckone  
It sounds like your hot plate wasn't getting the reaction mixture hot enough, then you flooded it with ethanol.
If too much water or ethanol is added then sulfuric acid loses its effectiveness as the catalyst.
In commercial operations the sulfuric acid is cycled to dry it.
Every mole of ether that is produced makes a mole of water.
edit:
You were using 95% ethanol, that contains water, you definitely flooded your reaction.

[Edited on 11-8-2020 by macckone]


correct, that must be the case.

that means my distillate is ethanol/water mostly?

this can be fractionally distilled to reuse the ethanol.

and the solution that is left from my reaction flask is sulfuric acid/ water mixture.
this can be boiled to re concentrate the sulfuric acid to 95% ?
then reuse


It just being ethanol explains why it took so long to distill over.
Stick some mgso4 in your 95%ethanol to get rid of the last traces of water and reconcentrate your sulfuric then try again how I described above
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[*] posted on 12-8-2020 at 00:03


Quote: Originally posted by draculic acid69  
Quote: Originally posted by LuckyWinner  
Quote: Originally posted by macckone  
It sounds like your hot plate wasn't getting the reaction mixture hot enough, then you flooded it with ethanol.
If too much water or ethanol is added then sulfuric acid loses its effectiveness as the catalyst.
In commercial operations the sulfuric acid is cycled to dry it.
Every mole of ether that is produced makes a mole of water.
edit:
You were using 95% ethanol, that contains water, you definitely flooded your reaction.

[Edited on 11-8-2020 by macckone]


correct, that must be the case.

that means my distillate is ethanol/water mostly?

this can be fractionally distilled to reuse the ethanol.

and the solution that is left from my reaction flask is sulfuric acid/ water mixture.
this can be boiled to re concentrate the sulfuric acid to 95% ?
then reuse


It just being ethanol explains why it took so long to distill over.
Stick some mgso4 in your 95%ethanol to get rid of the last traces of water and reconcentrate your sulfuric then try again how I described above


nilered and chemx youtube channels all drop ethanol into sulfuric acid and stirr heavy.
all other youtube channels do the same.

you ever made diethyl ether with your method successfully?

whats the advantage with your method over the usual way.
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draculic acid69
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[*] posted on 12-8-2020 at 06:47


Quote: Originally posted by LuckyWinner  
]

you ever made diethyl ether with your method successfully?

whats the advantage with your method over the usual way.


Clearly there's no advantage of this method over the usual way
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[*] posted on 13-8-2020 at 10:33



doing this diethyl ether reaction now again with erlenmeyer on hotplate with
spriral cooler and icewater.

its very slowly condensing, forming single tiny drops on the spirals at 39C...
it seems to be too slow again.

hotplate temp is 140C.
ethanol is very slowly dropped into the sulfuric acid/ethanol mixture.

cant see any ethylene gas escaping the tube...


can this reaction be paused and restarted the next day cause its taking 3 hours already
for a tiny amount of 39C distillate that came over.

does the reaction mixture degrade over the next 15 hours?
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[*] posted on 13-8-2020 at 10:55


or is my condenser getting to warm?
constant rechilling of the cooling water may be needed.

the diethyl ether guide mention's to drip the ethanol under the reaction mixture
to not cause it to evaporate immediately...

nilred or chemx do not do this...

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[*] posted on 13-8-2020 at 14:55


When distilling ether, the condenser and receiver can't be too cold. One is supposed to add water (or ROH) to acid, yes? No. Youtube video chemists may not entirely have their shit together? The old school way is seen in Fieser in the library.

[Edited on 13-8-2020 by S.C. Wack]




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draculic acid69
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[*] posted on 13-8-2020 at 18:43


Quote: Originally posted by LuckyWinner  


hotplate temp is 140C.
ethanol is very slowly dropped into the sulfuric acid/ethanol mixture.

?


The reaction mixture temp needs to be 140'c not the hotplate temperature.
When u say ethanol dripped into h2so4/ethanol mixture did u mean u mixed the sulfuric with ethanol before heating again?



[Edited on 14-8-2020 by draculic acid69]
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[*] posted on 14-8-2020 at 10:55


i know the reaction temp needs to be 140C but I had no 2 neck flask to insert a temperature probe.

fixed that problem now and will do this reaction again with reaction temp set to 140C.

diethyl ehter method that I did was,
cooled ethanol was put into flask, then sulfuric acid was dripped in slowly with heavy
mag stirring.
tiny glass shards were added for even boiling. (dont have acid wash sand)

hotplate is heated up slowly till solution starts boiling.
once condensation appeared at 35C, ethanol was slowly dripped into flask.


a question, I used magnetic stirring in my first experiments and just noticed today
that nobody is using mag stirring only acid wash sand, why?
I guess cause boiling hot sulfuric acid will eat my PTFE stir bar?

[Edited on 14-8-2020 by LuckyWinner]
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